What is the abnormality in a semen analysis with a volume of 2.5 milliliters (mL), 20 million sperm per milliliter (mL), 65% normal morphology, and 20% progressive forward mobility?

Semen Analysis Interpretation

The sample is abnormal due to a low percentage of forwardly mobile sperm (option D).

According to the World Health Organization (WHO) reference limits for human semen characteristics, the lower reference limit for progressive motility is 30% 1. The sample in question has only 20% progressive forward mobility, which falls below this threshold.

Analysis of Semen Parameters

Let's evaluate each parameter in the sample:

1. Volume: 2.5 mL

   • WHO lower reference limit: 1.4 mL 1
   • Assessment: NORMAL (above the lower reference limit)

2. Sperm Concentration: 20 million/mL

   • WHO lower reference limit: 16 million/mL 1
   • Assessment: NORMAL (above the lower reference limit)

3. Morphology: 65% normal forms

   • WHO lower reference limit: 4% 1
   • Assessment: NORMAL (well above the lower reference limit)

4. Progressive Motility: 20%

   • WHO lower reference limit: 30% 1
   • Assessment: ABNORMAL (below the lower reference limit)

Clinical Significance of Low Progressive Motility

Progressive motility is a critical parameter in semen analysis as it reflects the sperm's ability to travel through the female reproductive tract to reach and fertilize the egg. When progressive motility falls below 30%, it can significantly impact fertility potential 2.

Research has shown that low progressive motility correlates with reduced fertilization rates and pregnancy outcomes. Studies have demonstrated that the pregnancy rate is significantly reduced in cases with less than 40% progressively motile sperm (p < 0.001) 3.

Ruling Out Other Options

• Option A (normal but low volume): Incorrect because the volume of 2.5 mL is above the WHO lower reference limit of 1.4 mL 1.

• Option B (abnormal morphology): Incorrect because 65% normal morphology is well above the WHO lower reference limit of 4% 1, 4.

• Option C (inadequate sperm count): Incorrect because 20 million/mL is above the WHO lower reference limit of 16 million/mL 1.

Clinical Management Considerations

For patients with isolated asthenozoospermia (low motility):

• Consider antioxidant therapy for mild to moderate asthenozoospermia 2
• Repeat semen analysis after 3 months to assess response to treatment 2
• If no improvement after 3-6 months of appropriate therapy, consider referral for assisted reproductive technology (ART) 2
• For very severe asthenozoospermia, proceeding directly to IVF with ICSI may be recommended 2

Common Pitfalls in Semen Analysis Interpretation

• Focusing only on sperm count while ignoring other parameters like motility and morphology
• Using outdated reference values for semen parameters
• Failing to repeat abnormal semen analyses to confirm findings
• Not considering the comprehensive picture of all semen parameters together
• Overlooking the importance of progressive motility as a key predictor of fertility potential